Which type of plastic can be remolded or reshaped upon heating?

The ability to remold or reshape plastic when heated is characteristic of thermoplastics. This type of plastic consists of long polymer chains that can slide past one another when sufficient heat is applied. When heated, thermoplastics soften and become pliable, allowing them to be formed into various shapes. Upon cooling, they harden again, making them suitable for numerous applications. This property allows for easy recycling and reprocessing, which is a significant advantage in manufacturing and environmental considerations.

In contrast, thermosetting plastics, once heated and set into a shape, cannot be remolded or reshaped because they undergo a chemical change that hardens them permanently. Composite materials and fiberglass, although they may include thermoplastics, are not categorized based solely on the remolding property since they often involve a combination of materials to achieve specific strength and weight characteristics. Thus, thermoplastics are distinctively known for their ability to be reshaped upon reheating, making them the correct answer in this context.